Add helpful asterisk comments to the shadow demo. (#409)

* Add helpful asterisk comments to the shadow demo.

* Update FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/DemoTasks/ShadowDemoMainExample.c

* Add stuff to the license header for GHA checks.

FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/DemoTasks/ShadowDemoMainExample.c

@@ -1,5 +1,5 @@
 /*
- * FreeRTOS Kernel V10.3.0
+ * FreeRTOS V202011.00
  * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy of
@@ -19,9 +19,10 @@
  * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  *
- * http://www.FreeRTOS.org
- * http://aws.amazon.com/freertos
+ * https://www.FreeRTOS.org
+ * https://github.com/FreeRTOS
  *
+ * 1 tab == 4 spaces!
  */
 
 /*
@@ -589,26 +590,35 @@ void prvShadowDemoTask( void * pvParameters )
     /* Remove compiler warnings about unused parameters. */
     ( void ) pvParameters;
 
+    /****************************** Connect. ******************************/
+
     demoStatus = xEstablishMqttSession( &xMqttContext,
                                         &xNetworkContext,
                                         &xBuffer,
                                         prvEventCallback );
 
-    if( pdFAIL == demoStatus )
+    if( demoStatus == pdFAIL )
     {
         /* Log error to indicate connection failure. */
         LogError( ( "Failed to connect to MQTT broker." ) );
     }
-    else
+
+    if( demoStatus == pdPASS )
     {
-        /* First of all, try to delete any Shadow document in the cloud. */
+        /* Try to delete any Shadow document in the cloud. This is done to
+         * ensure possbile previous Shadow documents do not affect the state
+         * expected in the current demo. */
         demoStatus = xPublishToTopic( &xMqttContext,
                                       SHADOW_TOPIC_STRING_DELETE( democonfigTHING_NAME ),
                                       SHADOW_TOPIC_LENGTH_DELETE( THING_NAME_LENGTH ),
                                       pcUpdateDocument,
                                       0U );
+    }
+
+    /********************* Subscribe to Shadow topics. ************************/
+
+    /* Then try to subscribe the Shadow topics. */
 
-        /* Then try to subscribe shadow topics. */
     if( demoStatus == pdPASS )
     {
         demoStatus = xSubscribeToTopic( &xMqttContext,
@@ -630,10 +640,13 @@ void prvShadowDemoTask( void * pvParameters )
                                         SHADOW_TOPIC_LENGTH_UPDATE_REJECTED( THING_NAME_LENGTH ) );
     }
 
-        /* This demo uses a constant #democonfigTHING_NAME known at compile time therefore we can use macros to
-         * assemble shadow topic strings.
-         * If the thing name is known at run time, then we could use the API #Shadow_GetTopicString to
-         * assemble shadow topic strings, here is the example for /update/delta:
+    /********************* Publish to Shadow topics. **********************/
+
+    /* This demo uses a constant #democonfigTHING_NAME known at compile time
+     * therefore we can use macros to assemble shadow topic strings.
+     * If the thing name is known at run time, then we could use the API
+     * #Shadow_GetTopicString to assemble shadow topic strings, here is the
+     * example for /update/delta:
      *
      * For /update/delta:
      *
@@ -655,8 +668,8 @@ void prvShadowDemoTask( void * pvParameters )
      */
 
     /* Then we publish a desired state to the /update topic. Since we've deleted
-         * the device shadow at the beginning of the demo, this will cause a delta message
-         * to be published, which we have subscribed to.
+     * the device shadow at the beginning of the demo, this will cause a delta
+     * message to be published, which we have subscribed to.
      * In many real applications, the desired state is not published by
      * the device itself. But for the purpose of making this demo self-contained,
      * we publish one here so that we can receive a delta message later.
@@ -721,6 +734,8 @@ void prvShadowDemoTask( void * pvParameters )
         }
     }
 
+    /****************** Unsubscribe from Shadow topics. *******************/
+
     if( demoStatus == pdPASS )
     {
         LogInfo( ( "Start to unsubscribe shadow topics and disconnect from MQTT. \r\n" ) );
@@ -762,7 +777,9 @@ void prvShadowDemoTask( void * pvParameters )
         }
     }
 
-        /* The MQTT session is always disconnected, even there were prior failures. */
+    /****************************** Disconnect. *******************************/
+
+    /* The MQTT session is always disconnected, even if there were prior failures. */
     demoStatus = xDisconnectMqttSession( &xMqttContext, &xNetworkContext );
 
     /* This demo performs only Device Shadow operations. If matching the Shadow
@@ -781,7 +798,6 @@ void prvShadowDemoTask( void * pvParameters )
     {
         LogError( ( "Shadow Demo failed." ) );
     }
-    }
 
     /* Delete this task. */
     LogInfo( ( "Deleting Shadow Demo task." ) );